A few people have written in within the past 18 hours about their NTP server/clients getting set to the year 2000. The cause of this behavior is that an NTP server at the US Naval Observatory (pretty much the authoritative time source in the US) was rebooted and somehow reverted to the year 2000. This, then, propogated out for a limited time and downstream time sources also got this value. It's a transient problem and should already be rectified. Not much really to report except an error at the top of the food chain causing problems to the layers below. If you have a problem, just fix the year or resync your NTP server.

Just goes to show how reliant NTP is that it is all but a "fire and forget" service once configured until "bad things happen".